Collapsible tubing and method of producing the same



Dec. 21, 1943. CHERNACK 2,337,373

COLLAPSIBLE TUBING AND METHOD OF PRODUCING THE SAME Filed Jan. 29, 1945Even/ 50:"

ABEL E. CHERNACK V a his aiiiarneya Patented Dec. 21, 1943 COLLAPSIBLETUBING AND METHOD OF PRODUCING THE SAME Abel E. Chernack, Elmwood, Conn.

Application January 29, 1943, Serial No. 473,999

6 Claims. (01. 138-53) This invention relates to tubing and moreparticularly to flexible, collapsible tubing for conducting largevolumes of heated air under low pressures.

With the development of the airplane to its present large dimensionsthere has arisen need for flexible lightweight tubing for use in heatingthe engines, wings and windows. The large volume of heated air requirednecessitates a tubing of large diameter, which is preferably collapsiblefor convenient handling, while the temperature range to which suchtubing is subjected prevents the use of materials which tend to becomehard or brittle and crack at low temperatures, or the use of adhesiveswhich deteriorate with age or soften under heat. However, the tubing isof a construction which is not limited to use with tubing for heatingpurposes but may be used with tubing for other purposes where usualtemperatures are met and the usual materials can be used.

It is an object of this invention to provide a flexible, collapsibletubing constructed of materials which remain unaffected by temperaturechanges throughout the entire temperature range to which the tubing issubjected in use; which is with a substantially circular cross-sectionand having the side edges of the strip bent outwardly to form narrowflanges II and I2 at opposite sides of the opening l3. The metal spiralI0 is covered with a spirally wound strip 20 of a fiber glass, textileor other suitable material which is of slightly greater width than thepitch of the spiral l0 and has its opposite edges folded inwardly, as at2| and 22, adjacent the opposite faces of the strip. In wrapping thestrip 20 on the spiral Hi, the inwardly folded edge portions areinterlocked as shown in Fig. 3, the width of the strip 20, when applied,being such that the interlocked edge portions of the strip 20 lie on thespiral ID, as shown in Fig. 1.

A binding means 30, of wire, cord or other suitable material, is thenapplied, being wrapped about the covering strip 20 on the interlockededge portions in line with the opening l3 in the metal spiral I0 andunder suflicient tension to enlarge the opening l3 and draw theinterlocked edges of the strip 20 into the trough of the spiral l0. Asthe interlocked edges of the strip 20 are drawn through the opening l3they are folded so constructed that the use of adhesives is unnecessaryand the tubing remains sealed at all times; which is so constructed thatthere is no danger of contacting heated metal in the handling of thetubing; which can be manufactured of the diameters and in the continuouslengths desired; and which can be manufactured by a method suitable forrapid and economical production in commercial sizes and lengths. I It isalso an object of this invention to provide an improved method ofmanufacturing tubing of the class described.

In the drawing in which a tubing of preferred construction isillustrated,

Figure l is a perspective view of a short section of tubing constructedin accordance with this invention, a part of the tubing being brokenaway in order to show more clearly various stages in the manufacture ofthe tubing;

Figure 2 is a sectional view, drawn to a larger scale, through the seamof the finished tubing; and

Figure 3 is a sectional view, drawn to a larger scale, of theinterlocking joint formed in the covering material before theapplication of the binding wire cord.

As shown in the drawing, tubing in accordance with this inventioncomprises an inner spiral Hi consisting of a metal strip of atrough-shape about the binding means 30 and then the partial closing ofthe opening l3, by the resilience of the metal of the spiral l0, servesto cover the binding means with the interlocked portions of the strip 20and conceal the binding means 30 and cause the spiral Hi to cooperatewith the binding means 30 in locking the interlocked edges of the strip20 in the trough of the spiral Ill.

The binding of the interlocked edges of the strip 20 in the spiral It!prevents the opening of the tubing at the joint in the covering strip20, and the covering of the metal of the binding means or wire 30 andspiral In by the covering strip 20 insures against contact with heatedmetal in handling. Tubing thus constructed is of light Weight, even forlarge sizes, and collapsible so I that long lengths of large size tubingcan be conveniently handled or packed for shipment.

What is claimed is:

1. Tubing comprising a, spiral having a troughshaped cross section, aspirally wound covering strip on said spiral, said covering strip havingadjacent overlapping edges interlocked, and binding means securing theinterlocked edges of said covering strip in said spiral.

2. Tubing comprising a spiral of trough-shaped cross section, a spirallywound covering strip on said spiral, said covering .strip having itsedges overlapping along said spiral, and an outer binding means securingthe overlapping edges of said strip in the trough of said spiral.

3. Tubing comprising a spiral of trough-algal ins cross section, aspirally wound covering stri on said spiral, said covering strip havingoverla interlocked edges, and an outer binding means securing saidinterlocked edges in the trough of means about the overlapping edges ofsaid cover- 7 ing strip under sumcient tension to .rorce the edges ofthe covering strip into the trough of the spiral.

5. In a method of forming a tubing, the steps 01' forming a continuousspiral from a troughshaped strip, wrapping a covering'strip about saidspiral with the edges oi. said covering strip overlapping along saidspiral, wrapping a binding means about said covering strip along saidspiral, and forcing the overlapping strip edges into the trough of saidspiral by said binding means.

8. In a method of forming a tubing, the steps of forming a continuousspiral from a troughshaped strip, wrapping a covering strip about saidspiral, interlocking the adjacent edges of said covering strip alongsaid spiral, wrapping a binding means about said covering strip alongsaid spiral and under suiiicient tension to force the interlocked stripedges into the trough oi. said spiral and securing the interlocked stripedges in the trough or said spiral by the joint action of said spiraland binding means.

ABEL E CHERNACK.

